1. Field of the Invention.
This invention relates generally to corrosion inhibiting compositions and methods, and more particularly, to corrosion inhibiting compositions which form protective coatings on metal surfaces to inhibit the corrosive effects of oxidative environments in contact therewith.
2. Description of the Prior Art.
The corrosion of metal surfaces occurs when the surfaces are contacted by oxidative environments. Examples of such oxidative environments which are often in contact with metal surfaces include environments containing acids such as hydrochloric acid, nitric acid and sulfuric acid, environments containing water vapor in the presence of air or oxygen and environments associated with chloride or bromide ions, carbon dioxide and hydrogen sulfide.
Metal surfaces of tubular goods, heat exchangers and a variety of other equipment are often exposed to oxidative environments in industries such as the oil and chemical industries. For example, in the stimulation of oil and/or gas wells, aqueous solutions containing acids and/or other corrosive compounds are commonly utilized. When such fluids contact the metal surfaces of mixing tanks, pumps, casing, tubing and the like, the metal surfaces can be substantially corroded. Also, corrosive fluids are often produced from subterranean formations, e.g., brine, carbon dioxide and hydrogen sulfide, which can cause corrosion damage to metal surfaces in production and processing equipment. The corrosion of metal surfaces is increased when the surfaces are contacted by oxidative environments under elevated temperature and pressure conditions.
While a variety of corrosion inhibiting compositions and methods have been developed and used heretofore, there is a continuing need for improved corrosion inhibiting compositions and methods which are effective at high temperature and pressure conditions, are relatively inexpensive to produce and use and which provide residual protection for extended periods of time.